High speed rotary cutting tools capable of generating high quality work piece of varying diameters are generally known. For example, in the manufacture of valve seats for combustion engines, a circular seat with a gradually changing diameter is required for effecting adequate valve seating. A number of tools are available for accomplishing this task. Included are automated tools which rely on axially driven actuating bars. For example, Heuser, U.S. Pat. No. 3,025,729, discloses an automatic boring tool which employs a lever mechanism within a rotary housing which when engaged by an axially oriented drawbar, drives a slidably mounted tool bit radially outward. Faugli, et al, U.S. Pat. No. 3,477,340, employs a milling cutter and a support shank tiltably supported in a spindle. The cutting insert is radially directed by the rotation of a cylindrical shell surrounding the shank. As the shell rotates, the inclined planes of the shell cause only one side of the shell to rise thereby tilting the shank and radially extending the connected cutting insert.
A number of problems exist with the beforementioned high speed rotational cutters used in the production of valve seats that frequently operate at a turning speed of 500 rpm to 3000 rpm. An extension of a cutting bit radially typically creates a moment arm which destabilizes the tool. At an average rotating speed of 3000 rpm, a cutting insert weighing approximately 0.2 pounds generated a distance of 1 to 5 millimeters, creates approximately 60 to about 70 pounds of radially directed force. A high speed rotational cutting tool which provides automated radial cutter generation without the formation of an excess moment arm is therefore a highly desirable advance in the art of high speed rotating cutting tools.
Another object of the present invention is to facilitate reversible generation of a high speed cutting tool while at the same time, minimizing vibration and chatter.
Another object is to reversibly generate a cutting tool a predetermined distance along a workpiece with a high degree of accuracy and repeatability.
A further object of the present invention is to provide a high speed rotary cutting tool capable of generating a cutting edge over a substantial radial distance and produce a fine finish turning. Other objects will become apparent to those skilled in the art upon review of the specifications, claims and drawings.